<i>N</i>-Bromosuccinimide and Lithium Bromide: An Efficient Combination for the Dibromination of Carbon-Carbon Unsaturated Bonds
作者:Min Shi、Li-Xiong Shao
DOI:10.1055/s-2006-941558
日期:——
Compounds possessing unsaturated bonds such as alkenes, alkynes, allenes, and methylenecyclopropanes (MCPs) can be dibrominated within minutes by NBS and lithium bromide in THF at room temperature in good to excellent yields under mild conditions.
Dihalogenation ofgem-Aryl-Disubstituted Methylenecyclopropanes by DEAD, DIAD/TiX4 or Free Halogen
作者:Li-Xiong Shao、Lin-Jing Zhao、Min Shi
DOI:10.1002/ejoc.200400388
日期:2004.12
gem-aryl-disubstituted methylenecyclopropanes with TiX4/diethyl azodicarboxylate and TiX4/diisopropyl azodicarboxylate in 1,2-dichloroethane gave the dihalogenated ring-opened product, 2,4-dihalobut-1-ene, in moderate-to-excellent yields under mild conditions. On the basis of the proposed Orton-type mechanism, we found that this reaction can also be carried out with freehalogens such as bromine or iodine
Acetoxylation and Hydroxylation of Diarylmethylenecycloalkanes via Radical Approach
作者:Min Jiang、Yin Wei、Min Shi
DOI:10.1021/jo9027209
日期:2010.4.16
Diarylmethylenecycloalkanes were acetoxylated under the radical reaction conditions with PhI(OAc)(2), I-2, and TsNH2. Moreover, upon treating the products from the reactions of methylenecyclobutanes with N-bromosuccinimide (NBS) through silica gel column chromatography, the corresponding substituted methylenecyclobutanols were obtained in moderate to good yields. The plausible mechanisms have been proposed on the basis of the control experiments.
Novel Tunable CuX<sub>2</sub>-Mediated Cyclization Reaction of Cyclopropylideneacetic Acids and Esters for the Facile Synthesis of 4-Halomethyl-2(5<i>H</i>)-furanones and 4-Halo-5,6-dihydro-2<i>H</i>-pyran-2-ones
作者:Xian Huang、Hongwei Zhou
DOI:10.1021/ol026911q
日期:2002.12.1
[GRAPHICS]A mixture of cyclopropylideneacetic acids (or esters) and CuBr2 (or Cul/l(2)) in aqueous acetonitrile afforded 4-substituted 2(5H)-furanones or 3,4-substituted 5,6-dihydro-2H-pyran-2-ones in moderate to good yields. The selectivity of the reaction greatly depended on the reaction temperature.